1. Technical Field
The present invention pertains to a liquid droplet jetting head and a liquid droplet jetting apparatus and relates particularly to a liquid droplet jetting head that is disposed in a liquid droplet jetting apparatus and jets liquid droplets.
2. Related Art
Conventionally, there have been known liquid droplet jetting apparatus such as inkjet printers that perform printing by jetting ink liquid from a liquid droplet jetting head onto a recording medium.
This liquid droplet jetting head drives, in accordance with an image to be printed, plural drive elements installed in the head. For example, in a liquid droplet jetting head equipped with piezoelectric elements such as piezo elements as the drive elements, liquid droplets are jetted from nozzles as a result of a voltage being applied in accordance with drive data such that the piezoelectric elements deform.
In Japanese Patent Application Laid-Open (JP-A) No. 8-156257 and JP-A No. 11-263042, there is described a liquid droplet jetting head to which, as control signals that control the liquid droplet jetting head, are inputted a clock signal representing a synchronization timing of drive data, a signal line to which drive data are inputted and a latch signal representing a latch timing.
In this type of liquid droplet jetting head, drive data equal to a single jetting are serially inputted to the signal line and are stored in order in shift registers in synchronization with the clock signal. Additionally, the drive data stored in the shift registers are latched and held in latch circuits at a timing when the latch signal is inputted. Additionally, a voltage is applied to the piezoelectric elements in accordance with the drive data held in the latch circuit and jetting of ink is performed.
Further, in a liquid droplet jetting head, an output terminal is disposed in the liquid droplet jetting head and the drive data of the last stage of the shift registers are outputted in order from the output terminal. This is performed for the purpose of feeding back the drive back to verify their contents and cascade-connecting a plurality of the liquid droplet jetting heads. The liquid droplet jetting heads described in JP-A No. 8-156257 and JP-A No. 11-263042 are also equipped with an output terminal that outputs the drive data.
Incidentally, in recent years, increasing the density, number of elements and speed of a liquid droplet jetting head is being sought after. For example, assuming a 2-inch wide liquid droplet jetting head whose printing density is 1200 dpi, the number of drive elements reaches as much as 2400 elements per head.
When the number of drive elements significantly increases in this manner, there is a limit on transfer speed when serially transferring, with one signal line, drive data equal to a single jetting of each drive element. For this reason, a configuration that uses plural signal lines and performs serial transfer in parallel in each signal line is conceivable.
With such a configuration, the same number of output terminals and signal lines for feedback as the number of signal lines for input can become necessary when performing feedback of the drive data of each signal line. Further, in the case of a configuration that uses many of these heads, the affect thereof is even greater.
If the purpose is to check the drive data, a system that selects and sequentially checks one of the plural signal lines, for example, is also conceivable. However, in that case, it is necessary to transmit a selection control signal to the liquid droplet jetting head. Thus, eventually a terminal becomes necessary in order to input this selection control signal.
That is, it is necessary to increase the number of terminals for control data input in order to input each type of control data with respect to the liquid droplet jetting head.